Manufacture of flexible material from india-rubber and the like.



A. T. COLLIER.

MANUFACTURE OF FLEXIBLE MATERIAL FROM INDIA RUBBER AND THE LIKE.

APPLICATION 1 1L311 OCT. 8, 1910.

A 1,000,781 Patented Aug. 15, 1911.

W6 :52, e245 5 e15, fiZ 671 OT 2 (a ZZZe/ ARTHUR THOMAS COLLIER, OF ST.ALBANS, ENGLAND.\

MANUFACTURE OT FLEXIBLE MATERIAL FROM INDIA-RUBBER AND THE LIKE.

Specification of Letters Patent.

Patented Aug. 15, 1911.

Application filed October 8 1910. Serial No. 586,017.

To all whom it may concern:

Be it known that I, ARTHUR THOMAS COLLIER, a subject of the King ofGreat Britain, residing at St. Albans, Hertford shire, England, haveinvented a new and useful Improvement in the Manufacture of FlexibleMaterial from India-Rubber and the Like, of which the following is aspecification.

This invention relates to an improved manufacture of flexible, light,strong and waterproof material from india-rubber and the like, saidmaterial being useful in the manufacture of pneumatic and other vehicletires, of belting for conveyors or for the transmission of power, ofboot and shoe soles, the wheels of roller-skates, pneumatic balls suchas tennis and other playing balls,

- enemas or motor-horn bulbs, hose pipes and like articles whereflexibility and strength are required without stretching.

It has heretofore been suggested to mix cotton, flax, ramie or otherfiber in the natural or untwisted condition or fibers such as thoseobtained from rags, cloth or cotton waste, with suitable dough rubber inthe mixin mill, the whole being afterward vulcanize The material soformed, when used under some conditions, has been found to be deficientin strength and also to be liable to rise in temperature when subjectedto frequently repeated bending stresses such as occur for example in thedriving-wheel tires of a motor-vehicle of high power.

Now according to the present invention,

' in lieu of fibers such as above indicated, I

use for mixing with plastic composition suitable for vulcanization,fibers tightly twisted into individual threads, such for example assewing cotton, cut into short lengths, for example, in the case:of No.40 cotton, half an inch long. The length of the threads may be increasedin proportion to their thickness, but the threads must not be so long asto cause knotting or setting in lumps and so prevent intimate mixture. Ifind a suitable length for No. 12 sewing cotton or thread to beapproximately one inch. If. used in longer lengths-there is a tendencyfor the threads to become intertwined during the mixing process, andthus prevent a uniform distribution. The threads, either previouslytreated or not with a thin solution of india-rubber, are intimatelymixed with dough rubber in a mixing mill. This dough or plasticcomposition suitable for vulcanization preferably consists of Pararubber mixed with a suitable amount of sulfur to produce a flexiblevulcanized rubber when cured. It may however consist of sulfur and otherindiarubber, rubber substitutes or mixings of various rubbers or ofrubbers and rubber ing a number of tightly twisted threads Bincorporated therewith.

During the rolling of the material into sheets the threads tend toarrange themselves with their lengths in the direction of rolling sothat the sheet has less elasticity and greater tensile strength in thisdirection than in the transverse direction. I prefer to cut belting fromthe sheet in such a direction as to utilize this maximum strength. Butfor other urposes, such as vehicle tires, I may combine several layersso arranged that the directions of rolling of the different layers lieat right angles to one another. When the articles have been brought tothe desired shape or configuration, they are cured or vulcanized in anysuitable known manner.

By using individual threads as above described, I am enabled greatly'toincrease the strength of the material and also to use a largerproportionof cotton to india-rubber or the like than heretofore. I find that forheavy motor tires a good proportion is 20% of cotton threads to 80% ofrubber, though this amount of cotton may be increased to 30%, a ood dealdepending on the nature of the ru ber mixing, when such is employed. Forbelting, and general sheetin to take the place of what is known as theinsertion sheeting, in the rubber trade, about the same proportion issuitable, as also for boot soles, and such like goods. Forvalve-washers, and goods where a short thick shape is required withflexibility, a less proportion of cotton viz. 5% to 10% is preferable,while for hard goods approaching the uses of vulcanite, as much as 70%of cotton can be employed.

Since the surface of thread exposed to the rubber is smaller. than inthe case, Where fibers are used in a loose or untwisted condition, theelastic properties of the rubber are retained and the-liability of thema-' terial to crack when under bending stresses is reduced. Moreover,by reason of the fibers being tightly twisted 'the resultant tensilestrength is increased. Further, as the flexible material has a greatertensile strength, it can be used of a less thickness for any givenpurpose and thus the stress to'which the layers on the outside of a bendare subjected is reduced and the tendency to breakage is also reduced.Furthermore, the material keeps cooler when subjected to continuouslyvarying bending stresses such as are produced when it is made up in theform of vehicle tiresor driving belts. In cases where the material isused in the manufacture of pneumatic tires, it may be combined with alayer or layers of canvas arranged for example on the inner surface ofthe tire or tire cover.

One great advantage of this material over I insertion is that thematerial can be molded to any required shape without interfering withthe tensile strength of the material.-

curring in the appended claims is indicative of threads Whose lengthsvary between approximately one-half inch and one inch according to thecharacter. of the fibers of elements, as opposed to a Woven fabric wherethe threads are not separate but have a positive connection with eachother.

-I claim l. A process for the manufacture of a reinforced flexiblematerial consisting in intimately mixing with a plastic compositionsuitable for vulcanization individual short lengths of thread composedof fibers tightly twisted together, bringing the mixture to the desiredshape of the finished article, and then vulcanizing the same.

2. A process for the manufacture of a reinforced flexible materialconsisting in intimately mixing with an india-rubber dough suitable forvulcanization individual short lengths of thread composed of fiberstightly twisted together, bringing the mixture to the desired shape ofthe finished article, and then vulcanizing the same.

3. A composition of matter consisting of an intimate mixture of aplastic vulcanized material and individual short lengths of threadcomposed of fibers tightly twisted together.

4. A composition of matter consisting of an intimate mixture ofvulcanized indiarubber and individual short lengths of thread composedof fibers tightly twisted together.

ARTHUR THOMAS COLLIER.

Witnesses:

H. D. JAMEsoN, R. WESTACOTT.

